Hillary Clinton threatened to “ring” China with defensive missiles if Beijing did not rein in North Korea, leaked emails detailing a private speech she made three years ago claim.

The US democratic presidential candidate also blamed the Chinese military for being Pyongyang’s biggest ally, according to the hacked emails, which were revealed by Wikileaks.

The former secretary of state’s comments reflect ongoing frustrations in Washington that China has been failing to use its influence as North Korea’s biggest trading partner and ally to encourage the regime to cease its nuclear weapons programme.

The threat of an increased US military profile in the region would cause alarm in China, which expressed anger in July after Seoul’s decision to deploy a US anti-missile defence system to counter threats from North Korea.

Pyongyang conducted its fifth nuclear test earlier this year, and Beijing claims its influence is limited with the country's leaders.

“You know, we all have told the Chinese if they (North Korea) continue to develop this missile program and they get an ICBM (Intercontinental Ballistic Missile) that has the capacity to carry a small nuclear weapon on it, which is what they’re aiming to do, we cannot abide that,” Mrs Clinton told a Goldman Sachs conference in June 2013, according to the leaked data.

“Because they could not only do damage to our treaty allies, namely Japan and South Korea, but they could actually reach Hawaii and the West Coast theoretically, and we’re going to ring China with missile defence.

“We’re going to put more of our fleet in the area. So China, come on. You either control them or we’re going to have to defend against them.”

Then US Secretary of State Hillary Clinton meets then Chinese Premier Li Keqiang in September 2012Credit:
Pool/AP

Mrs Clinton also said: “The biggest supporters of a provocative North Korea has been the PLA (People’s Liberation Army).”

The speeches emerged in emails from her campaign chairman's personal account.

The validity of the emails – which offer a glimpse into how she might act if she becomes the US president – have not been verified or denied by the Clinton team, according to US media.

Other excerpts show that Mrs Clinton told Chinese officials that she opposed Beijing’s expansive claims over the strategically important South China Sea.

She said that China’s claims over the disputed waters were based on “pottery shards from, you know, some fishing vessel that ran aground in an atoll somewhere”, and that by that reasoning, the US could claim the Pacific Ocean.

“We liberated it, we defended it. We have as much claim to all of the Pacific. And we could call it the American Sea, and it could go from the West Coast of California all the way to the Philippines,” she allegedly said.